YOKOGAWA TB820D, User Manual, Page: 26 / 87

<2. INSTALLATION, PIPING, AND WIRING>
2-15
IM 12B01B30-02EN 2nd Edition : June 09 , 2021-00
The piping diagram of a system including the pressurized head tank is shown in Figure 2.24.
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Sample
Inlet
Drain Port
Sample
Outlet
Detector
Drain Valve
Sample
Tap Water
Sample
Valve
Zero Turbidity
Filter
Sample
Supply Valve
Zero Water Supply Valve
Tap Water
Valve
Drain
Drain
Drain
Sample
Pressurized
Head Tank
Zero Water
Bypass Valve
Flow Control Valve
Sample
Effluent
Zero Water
Drain Valve
Other Turbidity Detectors
Pressure
Gauge
Figure 2.24 Piping Diagram (/D1)
(1) Piping of the Sample Line to the Detector
This piping is for introducing a sample into the measurement cell of the detector. Install a
pressurized head tank (for low turbidity), valves and pipes by referring to the diagram in Figure
2.24.
1. For the piping from a sampling point to a sample valve, use a hose/tube with sufficient
diameter that provides adequate flow of sample in order to prevent clogging. The hose/tube
also should withstand the sample pressure. The specified sample pressure when using a
pressurized head tank is in the range of 20 to 500 kPa. One example is a rigid PVC tube
with nominal size of 16 (22 mm OD).
2. For the piping between the valve and the pressurized head tank, use a 8 mm OD x 6 mm ID
polyethylene tube and the corresponding fitting.
3. To the sample inlet of the detector, attach a 3-way (tee) or appropriate fitting corresponding
to the inlet’s connection size (Rc1/2 or 1/2 NPT). This allows switching of the sample flow
and the zero water flow.
4. For the piping between the Pressurized Head Tank and the Detector, connect a valve to one
end of the 3-way tee fitting and connect a 8 mm OD x 6 mm ID polyethylene tube and the
corresponding fitting between the valve and the pressurized head tank.
5. To the fitting on the bypass valve (needle valve) at the top of the pressurized head tank,
connect a 8 mm OD x 6 mm ID polyethylene tube.
6. To prevent clogging or stagnation of air bubbles in the pipe line, install the pipes so that no
bends or stagnation occurs.